Propulsion unit comprising at least one electric motor and a coupling system positioned on either side of a transmission system

Abstract

A propulsion unit comprising a propulsion system, at least one electric motor positioned in a first external zone, a transmission system, a coupling device which comprises: a first coupling shaft coupled to an output of the electric motor, passing through the transmission system and having a first end protruding into a second external zone; a second coupling shaft coupled to an input of the transmission system, passing through at least one wall of the transmission system and having a first end protruding into the second external zone; and a coupling system configured to couple the first ends of the first and second coupling shafts in terms of rotation and which is positioned in the second external zone. Also an aircraft having at least one such propulsion unit.

The invention claimed is: 
     
         1 . A propulsion unit comprising:
 a propulsion system,   at least one electric motor,   a coupling device, and,   a transmission system which is coupled to the propulsion system, the transmission system comprising a first transverse wall and a second transverse wall which delimit an internal zone which is located between the first and second transverse walls, a first external zone separated from the internal zone by the first transverse wall, a second external zone separated from the internal zone by the second transverse wall, the at least one electric motor connected to the first transverse wall and positioned in the first external zone, and the at least one electric motor having an output coupled by the coupling device to an input of the transmission system which is positioned in the internal zone,   wherein the coupling device comprises:
 a first coupling shaft which is coupled to the output of the electric motor, passing through the transmission system and having a first end protruding into the second external zone, 
 a second coupling shaft which is coupled to the input of the transmission system, passing through at least the second transverse wall and having a first end protruding into the second external zone, 
 a coupling system which is configured to couple the first ends of the first and second coupling shafts in terms of rotation and which is positioned in the second external zone 
 wherein the second coupling shaft is hollow and is configured to house the first coupling shaft. 
   
     
     
         2 . The propulsion unit as claimed in  claim 1 , wherein the first and second coupling shafts are coaxial. 
     
     
         3 . The propulsion unit as claimed in  claim 1 , wherein the coupling system is positioned inside the second coupling shaft. 
     
     
         4 . The propulsion unit as claimed in  claim 3 , wherein the coupling device comprises a plug configured to seal the first end of the second coupling shaft and connected by a releasable connection to the second coupling shaft. 
     
     
         5 . The propulsion unit as claimed in  claim 1 , wherein the at least one electric motor comprises an output shaft passing through the transmission system, and
 wherein the output shaft and the first coupling shaft form one and the same shaft.   
     
     
         6 . The propulsion unit as claimed in  claim 1 , wherein the at least one electric motor comprises an output shaft positioned in the first external zone, and
 wherein the first coupling shaft and the output shaft are two separate shafts, the first coupling shaft comprising a second end which is positioned in the first external zone and coupled to the output shaft of the electric motor.   
     
     
         7 . The propulsion unit as claimed in  claim 1 , wherein the second coupling shaft comprises a second end which cooperates with the first transverse wall, and
 wherein the propulsion unit further comprises   a pivoting connection comprising a first rotating guide interposed between a portion of the second coupling shaft and the second transverse wall, and   a second rotating guide interposed between the second end of the second coupling shaft and the first transverse wall.   
     
     
         8 . The propulsion unit as claimed in  claim 1 , wherein the propulsion system is positioned in the second external zone. 
     
     
         9 . The propulsion unit as claimed in  claim 1 , wherein the coupling system is configured to be disengaged and is configured to adopt a coupled state in which the output of the electric motor is coupled in terms of rotation and transmits a rotational movement to the input of the transmission system and to adopt an uncoupled state in which the output of the electric motor is no longer coupled to the input of the transmission system and no longer transmits any rotational movement thereto. 
     
     
         10 . The propulsion unit as claimed in  claim 9 , wherein the coupling system is configured to pass from the coupled state to the uncoupled state as soon as a torque transmitted via the coupling system exceeds a given threshold or is no longer within a given range. 
     
     
         11 . The propulsion unit as claimed in  claim 1 , wherein the coupling system comprises a freewheel configured to adopt a state which is coupled in terms of rotation and in which the first coupling shaft is coupled in terms of rotation and transmits a rotational movement to the second coupling shaft, and to adopt an uncoupled state in which the first coupling shaft is no longer coupled in terms of rotation to the second coupling shaft and no longer transmits any rotational movement thereto. 
     
     
         12 . An aircraft comprising:
 at least one propulsion unit as claimed in  claim 1 .